Idaho semi-weekly world. [volume] (Idaho City, Idaho Territory) 1875-1908, 1887-05-06
HOW TO MAKE GLASS.
The Process Of Manufactures Of the different
Kinds.

srial Training School, lectured at
Franklin Institute recently on "Glass
Making" After briefly retailing the
history OF the art ofmaking glass, and
what glass was, Mr.. Henderson said;
1.-THE operation OF glass-making re-
quires both skill and patience; nicely
in the mixture of the materials and
1elicacy and dexterity in the manu-
facture OF the finished product. There
is no industry SO benefited by tho
discovery Unnatural gas as this. Euro
pean manufacturers have long used ar
tilicial gas, it having been found that
smoke and sulphurous fumes from the
coal affected the clearness OF the pro-
duct. Where. in this country, nat
ural gas is not obtainedable. man.
ufactured gus is taking the place OF
coal in the principal furnaces. In the
furnace huge pots OF iire-clay, with
| capacity of 1,4o0 to 1000 pounds
Of material. are filed with the
mixed substances called the batch,
composed OF sand, lime and carbon
| ate or sulphate OF soda in varying
proportions. Into chamber beneath
them the burninggas streams. Above
! each pot is an opening into the cham
| Der in which it stands, through which
the blowpipe is dipped into its con
| tents. The blowpipe is heavy tube
| OF wrought iron, it's lower end some
| what Hanged.
In making the window glass, the OPP
! orator repeatedly dips his pipe into
the molten glass, until on it's end is q
mass OF fused glass. Whirling this
| rapidly and dexterously it assumes @,
pear-like shape The operator
blows into the pipe, mould
ing the huge bubble as it grows to the
| size and shape of a carboy. The blow
| ing now ceases, and the operator
| swings his bubble in q pit beneath his
| platform, until by it's weight it length
| ems into a cylinder and cools to hard
| ness. The top and bottom of this
| cylinder are ingeniously got rid of,
and cold IRON is run along one side
| the remaining cylinder, making q
| straight crack through its entire length.
! 1t is then put into an oven, crack up
| permost, as it is heated it falls out in
| to flat plate and is ''ironed smooth"
| by fiat piece of wood on the end OF
Il long bar. Lastly, it is put into the
! annealina furnace heated and allow
ed to cool very gradually, to tougher
the glass. 1t may then be cut up into
panes. Crown glass is made by gath
ering the mass in the end OF the pipe,
blowing q small bubble and transfer
ring it to an iron bar. The opening
left by the blowpipe is gradually en-
larged as the mass is whrled until the
mass becomes circular fiat disk. It's
disadvantages are it's variable thick
ness and the smallness OF the panes.
Plate glass is OF the same compost
ton as the former, but purer materi-
ais are used. 1t is cast on an iron or
bronze table from q huge ladle swung
from the furnace to the table. Rollers
pass over it to secure uniform thick
ness. The result is rough slab, only
translucent. 1t is made smooth with
sand and emery, and polished with
burnt sulphate OF iron.
In making the batch for optical
glass lead is used instead of lime. This
> branch of the art reaches it's highest
perfection in America, and all the i'm
portant lenses for telescopes are made
on this side OF the Atlantic Another
flat glass is seen in the car windows
! the design being pressed into the heat
ed pane. and the marks subsequently
polished.
Mosaic glass is, translucent, colored
unevenly by arsenic, tin and Other
compounds, and is coming into use il
: preference to stained glass, it's dura
bility and richness of shading being
superior to the latter.
1t is cast in small pieces, the opera
! tor himself not knowing exactly how
the product will look, and the artist
: consequently Gun not have his piece:
made to order. A memorial window
/, in Milwaukee, made OF this glass, th'
: subject being Christ Leaving the Hal
: OF Justice, contains 200 figures.
Mr.. Yunk then made in miniature
, from glass tubes, some of the articles
: Briefly describing the process he said
! 'Hollow-ware is either blown or press
7 ed The furnace used in making it i
: the Ferrari or tank furnace, the no
air impinging on constantly renewe,
! heap OF material in q reverberator,
. chamber, the fused product flowin
= away into tank, With openings abov
1T similar to those in other furnaces. B,
this process work is kept up continu
ously in blast from fall to spring. TIL
mass on the blow pipe is put into
mould, which closes upon it while tn
t operator blows into it; the necks ar
: finished afterwards in an oxy-hydro
4 gen flame. Finer holloware is mould
! ed in the air entirely, its surface bein
u much brighter and smoother.
n Pressed glassware is made by poul
n ing the motion glass into meta
: mould, and another mould fitted t
its inside surface, pressed heavily int
g 1t. 1t is made in imitation OF Gu
n glass, but it distinguishable from
Y by the dullness of it's edges, caused b
q the product shrinking as it cools Gu
=. glass, however, Is now made from i
the article being pressed into shar
J aad the design ground clear and shar
a with fine copper wire covered wit
, sand"